This invention relates to the domain of lighting for a motor vehicle. More specifically, the invention relates to an optical system for a headlamp.
Motor vehicles contain numerous lighting devices for both interior and exterior illumination. For example, exterior vehicle lighting devices may perform stop lamp functions, tail lamp functions, headlamp functions, daytime running light functions, dynamic bending light functions, and fog lamp functions.
Most states, countries, or regions which utilize motor vehicles have various requirements and standards that a vehicle must adhere to in order to legally use roadways. For example, Federal Motor Vehicle Safety Standard (FMVSS) No. 108 specifies various maximum and minimum photometric intensity values (based on angle) for headlamps on vehicles operated within the Unites States.
The Insurance Institute for Highway Safety (IIHS) in the United States has its own set of tests and ratings (Headlight Test and Rating Protocol) for headlamp performance. The IIHS tests and ratings seek to encourage manufacturers to improve the illumination performance in actual on-road use.
IIHS evaluations have shown that the on-road illumination provided by vehicle headlamps varies widely. In addition, IIHS has rated the majority of headlamps in a poor category (e.g. insufficient illumination, excessive glare, etc.). The IIHS testing protocol tests headlamp for 5 curve conditions: 1/150 meter radius Left curve, 2/250 meter radius Left curve, 3/Straight roadway, 4/250 meter Right curve, and 5/150 meter Right curve.
In recent years, vehicle lighting has also become important for its aesthetic appeal to consumers. It may be technically challenging to provide aesthetically appealing vehicle lighting devices while also meeting the necessary cost, technology, and regulatory requirements. For example, reducing lens's height for lighting modules requires using LEDs with higher luminance (cd/mm2) than conventional products to meet regulation requirements at the testing points.
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as conventional art at the time of filing, are neither expressly nor impliedly admitted as conventional art against the present disclosure.